<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .progress {
        height: 25px;
        width: 400px;
        border-radius: 15px;
        background-color: #272425;
        border: 3px solid #272425;
        box-sizing: border-box;
        margin-bottom: 30px;
      }
      .inner {
        width: 50%;
        height: 20px;
        border-radius: 10px;
        text-align: right;
        position: relative;
        background-color: #409eff;
        background-size: 20px 20px;
        box-sizing: border-box;
        transition: all 1s;
      }
      .inner span {
        position: absolute;
        right: -20px;
        bottom: -25px;
      }
    </style>
  </head>
  <body>
    <div id="app">
      <div class="progress">
        <div class="inner" :style="{ width }">
          <span>{{ width }}</span>
        </div>
      </div>
      <button @click="setWidth('25%')">设置25%</button>
      <button @click="setWidth('50%')">设置50%</button>
      <button @click="setWidth('75%')">设置75%</button>
      <button @click="setWidth('100%')">设置100%</button>
    </div>
    <script src="./vue.js"></script>
    <script>
      const app = new Vue({
        el: '#app',
        data: {
          width: '50%',
        },
        methods: {
          setWidth(width) {
            this.width = width;
          },
        },
      });
    </script>
  </body>
</html>
